The present common curtain devices are used for shading sunlight or serving as a decoration, and these devices usually adopt a pulling string to roll the curtain up or down. However, such curtain is applicable for the Venetian curtain or the curtains that can be opened or closed sideway (from a left side or a right side), but it is not applicable for the one-piece curtains. The aforementioned curtain still has the following unsolved problems:
(1) The pulling string of the prior art curtain is pulled to the right slanting direction and then to a vertical direction, so that the curtain cloth can be opened completely. If the pulling string is pulled towards the right inclined direction, the pulling string will be stuck, and the whole curtain cloth will be rolled up to the top, and such pulling movement cannot fully control the curtain cloth to be opened or rolled up to a desired height.
(2) The prior art curtain cannot meet the user's requirements or roll the curtain cloth up or down to fix the curtain cloth to a desired height, and thus affecting the overall applicability of the curtain.